Absurd Attempt to Link Climate Change to Cancer Contradicted by Another Medical Study

Extreme weather has already been wrongly blamed on climate change. More outlandish claims have linked climate change to medical and social phenomena such as teenage drinking, declining fertility rates, mental health problems, loss of sleep by the elderly and even Aretha Franklin’s death.

Now the most preposterous claim of all has been made, that climate change causes cancer. A commentary last month in a leading cancer journal contends that climate change is increasing cancer risk through increased exposure to carcinogens after extreme weather events such as hurricanes and wildfires. Furthermore, the article declares, weather extremes impact cancer survival by impeding both patients' access to cancer treatment and the ability of medical facilities to deliver cancer care.

How absurd! To begin with, there’s absolutely no evidence that global warm­ing triggers extreme weather, or even that extreme weather is becoming more frequent. The following figure, depicting the annual number of global hurricanes making landfall since 1970, illustrates the lack of any trend in major hurricanes for the last 50 years – during a period when the globe warmed by ap­proximately 0.6 degrees Celsius (1.1 degrees Fahrenheit). The strongest hurricanes today are no more extreme or devastating than those in the past. If anything, major landfalling hurricanes in the US are tied to La Niña cycles in the Pacific Ocean, not to global warming.

And wildfires in fact show a declining trend over the same period. This can be seen in the next figure, displaying the estimated area worldwide burned by wildfires, by decade from 1900 to 2010. While the number of acres burned annually in the U.S. has gone up over the last 20 years or so, the present burned area is still only a small fraction of what it was back in the 1930s.

Apart from the lack of any connection between climate change and extreme weather, the assertion that hurricanes and wildfires result in increased exposure to carcinogens is dubious. Although hurricanes occasionally cause damage that releases chemicals into the atmosphere, and wildfires generate copious amounts of smoke, these effects are temporary and add very little to the carcinogen load experienced by the average person.

A far greater carcinogen load is experienced continuously by people living in poorer countries who rely on the use of solid fuels, such as coal, wood, charcoal or biomass, for cooking. Incomplete combustion of solid fuels in inefficient stoves results in indoor air pollution that causes respiratory infections in the short term, especially in children, and heart disease or cancer in adults over longer periods of time.

The 2019 Lancet Countdown on Health and Climate Change, an annual assessment of the health effects of climate change, found that mortality from climate-sensitive diseases such as diarrhea and malaria has fallen as the planet has heated, with the exception of dengue fever. Although the Countdown didn’t examine cancer specifically, it did find that the number of people still lacking access to clean cooking fuels and technologies is almost three billion, a number that has fallen by only 1% since 2010.

What this means is that, regardless of ongoing global warming, those billions are still being exposed to indoor carcinogens and are therefore at greater-than-normal risk of later contracting cancer. But the cancer will be despite climate change, not because of it – completely contradicting the claim in the cancer journal that climate change causes cancer.

Because climate change is actually reducing the frequency of hurricanes and wildfires, the commentary’s contention that extreme weather is worsening disruptions to health care access and delivery is also fallacious. Delays due to weather extremes in cancer diagnosis and treatment initiation, and the interruption of cancer care, are becoming less, not more common.

It makes no more sense to link climate change to cancer than to avow that it causes hair loss or was responsible for the creation of the terrorist group ISIS.

Next: Science vs Politics: The Precautionary Principle

Science on the Attack: Cancer Immunotherapy

As a diversion from my regular blog posts examining how science is under attack, occasional posts such as this one will showcase examples of science nevertheless on the attack – to illustrate the power of the scientific method in tackling knotty problems, even when the discipline itself is under siege. This will exclude technology, which has always thrived. The first example is from the field of medicine: cancer immunotherapy.

Cancer is a vexing disease, in fact a slew of different diseases, in which abnormal cells proliferate uncontrollably and can spread to healthy organs and tissues. It’s one of the leading causes of death worldwide, especially in high-income countries. Each type of cancer, such as breast, lung or prostate, has as many as 10 different sub-types, vastly complicating efforts to conquer the disease.

Although the role of the body’s immune system is to detect and destroy abnormal cells, as well as invaders like foreign bacteria and viruses, cancer can evade the immune system through several mechanisms that shut down the immune response.

One mechanism involves the immune system deploying T-cells – a type of white blood cell – to recognize abnormal cells. It does this by looking for flags or protein fragments called antigens displayed on the cell surface that signal the cell’s identity. The T-cells, sometimes called the warriors of the immune system, identify and then kill the offending cells.

But the problem is that cancer cells can avoid annihilation by deactivating a switch on the T-cell known as an immune checkpoint, the purpose of which is to prevent T-cells from becoming over zealous and generating too powerful an immune response. Switching off the checkpoint altogether takes the T-cell out of the action and allows the cancer to grow. The breakthrough of cancer immunotherapy was in discovering drugs that can act as checkpoint inhibitors, which keep the checkpoint activated or switched on at all times and therefore enable the immune system to do its job in attacking the cancerous cells.

However, such a discovery wasn’t an easy task. Attempts to harness the immune system to fight cancer go back over 100 years, but none of these attempts worked successfully on a consistent basis. The only options available to cancer patients were from the standard regimen of surgery, chemotherapy, radiation and hormonal treatments.

In what the British Society for Immunology described as “one of the most extraordinary breakthroughs in modern medicine,” researchers James P. Allison and Tasuku Honjo were awarded the 2018 Nobel Prize in Physiology or Medicine for their discoveries of different checkpoint inhibitor drugs – discoveries that represented the culmination of over a decade’s painstaking laboratory work. Allison explored one type of checkpoint inhibitor (known as CTLA-4), Honjo another one (known as PD-1).

Early clinical tests of both types of inhibitor showed spectacular results. In several patients with advanced melanoma, an aggressive type of skin cancer, the cancer completely disappeared when treated with a drug based on Allison’s research. In patients with other types of cancer such as lung cancer, renal cancer and lymphoma, treatment with a drug based on Honjo’s research resulted in long-term remission, and may have even cured metastatic cancer – previously not considered treatable.

Yet despite this initial promise, it’s been found that checkpoint inhibitor immunotherapy is effective for only a small portion of cancer patients: genetic differences are no doubt at play. States Dr. Roy Herbst, chief of medical oncology at Yale Medicine, “The sad truth about immunotherapy treatment in lung cancer is that it shrinks tumors in only about one or two out of 10 patients.” More research and possibly drug combinations will be needed, Dr. Herbst says, to extend the revolutionary new treatment to more patients.

Another downside is possible side effects from immune checkpoint drugs, caused by overstimulation of the immune system and consequent autoimmune reactions in which the immune system attacks normal, healthy tissue. But such reactions are usually manageable and not life-threatening.

Cancer immunotherapy is but one of many striking recent advances in the medical field, illustrating how the biomedical sciences can be on the attack even as they come under assault, especially from medical malfeasance in the form of irreproducibility and fraud.

Next: Coronavirus Epidemiological Models: (1) What the Models Predict

Corruption of Science: The Reproducibility Crisis

One of the more obvious signs that modern science is ailing is the reproducibility crisis – the vast number of peer-reviewed scientific studies that can’t be replicated in subsequent investigations and whose findings turn out to be false. In the field of cancer biology, for example, researchers discovered that an alarming 89% of published results couldn’t be reproduced. Even in the so-called soft science of psychology, the rate of irreproducibility hovers around 60%. And to make matters worse, falsification and outright fabrication of scientific data is on the rise.

The reproducibility crisis is drawing a lot of attention from scientists and nonscientists alike. In 2018, the U.S. NAS (the National Association of Scholars in this case, not the Academy of Sciences), an academic watchdog organization that normally focuses on the liberal arts and education policy, published a particularly comprehensive examination of the problem. Although the emphasis in the NAS report is on the misuse of statistical methods in scientific research, the report discusses possible causes of irreproducibility and presents a laundry list of recommendations for addressing the crisis.

The crisis is especially acute in the biomedical sciences. Over 10 years ago, Greek medical researcher John Ioannidis argued that the majority of published research findings in medicine were wrong. This included epidemiological studies in areas such as dietary fat, vaccination and GMO foods as well as clinical trials and cutting-edge research in molecular biology. 

In 2011, a team at Bayer HealthCare in Germany reported that only about 25% of published preclinical studies on potential new drugs could be validated. Some of the unreproducible papers had catalyzed entirely new fields of research, generating hundreds of secondary publications. More worryingly, other papers had led to clinical trials that were unlikely to be of any benefit to the participants.

Author Richard Harris describes another disturbing example, of research on breast cancer that was conducted on misidentified skin cancer cells. The sloppiness resulted in thousands of papers being published in prominent medical journals on the wrong cancer. Harris blames the sorry condition of current research on scientists taking shortcuts around the once venerated scientific method.

Cutting corners to pursue short-term success is but one consequence of the pressures experienced by today’s scientists. These pressures include the constant need to win research grants as well as to publish research results in high-impact journals. The more spectacular that a paper submitted for publication is, the more likely it is to be accepted, but often at the cost of research quality. It has become more important to be the first to publish or to present sensational findings than to be correct.      

Another consequence of the bind in which scientists find themselves is the ever increasing degree of misunderstanding and misuse of statistics, as detailed in the NAS report. Among other abuses, the report cites spurious correlations in data that researchers claim to be “statistically significant”; the improper use of statistics due to poor understanding of statistical methodology; and the conscious or unconscious biasing of data to fit preconceived ideas.

Ioannidis links irreproducibility to the habit of assigning too much importance to the statistical p-value. The smaller the p-value, the more likely it is that the experimental data can’t be explained by existing theory and that a new hypothesis is needed. Although p-values below 0.05 are commonly regarded as statistically significant, using this condition as a criterion for publication means that one time in twenty, the experimental data could be the result of chance alone. The NAS report recommends defining statistical significance as a p-value less than 0.01 rather than 0.05 – a much more demanding standard.

The report further recommends integration of basic statistics into curricula at high-school and college levels, and rigorous educational programs in those disciplines that rely heavily on statistics. Beyond statistics, other suggested reforms include having researchers make their data available for public inspection, which doesn’t often occur at present, and encouraging government agencies to fund projects designed purely to replicate earlier research, which again is rare today. The NAS believes that measures like these will help to improve reproducibility in scientific studies as well as keeping advocacy and the politicization of science at bay.

Next week: Corruption of Science: Scientific Fraud